I don't try to act nice
In public, I never try to act nice to others. I stay in my own space.
Because what happens is that people approach me, assuming that they can take advantage of my good will if I am nice.
For some reason, people see me and want to talk to me. But they want to ask me for money, or for "help".
But it's always the same people, panhandlers, people that have no need to ask for help. People that have a devious look to them.
I'm convinced physiognomy is true. You can tell someone's personality based on how they look.
So no, I never try to act nice, I am nice when I see that someone is worth being nice to. But most people aren't, most people just take advantage of kindness.
And people think a strangers kindness is owed to them. It is not. If we are strangers, I owe you basic decency, but nothing else, and you owe me nothing back.